For those you considering a chassis cab, the suspension is stiff when unloaded unless you go with an aftermarket air suspension system. For those of you that like to "put foot your into it", you may also be disappointed at the tune used on these trucks. They are detuned to allow longer duty cycles at full output. My 2005 6.0 PSD had the same horsepower as my current 2015 6.7 CTD, but I have never felt a need or want for more since I have other vehicles that can fulfill my need speed much better than a truck.